Non-parametric statistics. A how-to guide.

What is it about?

This paper is the second of a short series of articles aimed towards describing some of the various statistical methods and approaches that have been used in surface finishing. The methods fall broadly into two areas: analysis and design-of-experiments. In the first paper, the subject was briefly introduced followed by a discussion of parametric statistics hypothesis testing. This second paper logically continues with descriptions of the various non-parametric tests and situations where these could be applied. Examples are provided from within the context of surface finishing applications, although the application of the described tests can be more universally applied.

Why is it important?

The understanding and use of statistics is important in all research methods. This paper is the second in a series, describing non-parametric statistical methods. The paper will be a good reference source for anyone needing a good grasp of when and how to apply non-parametric statistical methods. A light-touch mathematical approach is adopted which gives some detail about what's happening within the SPSS 'black box.

Perspectives

Dr James R Smith (Author)

University of Portsmouth

Free downloads of the post-print versions of the Part 1 (parametric stats) and Part 2 (non-parametric stats) are available from the Resources section.